U.S. Pat. No. 3,598,212, GIESE, describes a one-way structure in which a retainer ring forming, for example, a clutch sprag or clutch element, in a cage ring, is located between a coaxially placed driving member and a driven member. The ring is formed as a central ring with elongated holes in which tiltable sprags are disposed. The sprags can be inserted in a predetermined first angular position in openings of the ring or cage, and are then pivoted under influence of a spring into their normal or quiescent position. The sprags are retained in place by interengaging projections or heads which project in circumferential direction with respect to the central or a pinched zone of the sprags, so that the sprags are automatically retained against removal from the cage, even before the cage is installed or assembled between an inner race and an outer race forming, respectively, a driven and a driving element of the one-way clutch.
Assembling the sprags is possible only with sprag elements which have a pinched central portion. Spring elements which are essentially of circular appearance cannot be assembled in this manner. Sprag elements with essentially circular shape, however, are substantially cheaper to make. Such sprag elements are, usually, guided on bowed, roughly radially extending guide surfaces of the cage, being guided in circumferential direction. No projecting head elements which prevent removal of the sprags can be present in such a construction, so that loss of sprag elements during and before assembly is difficult to prevent. Assembly of such essentially circular clamping or sprag elements may be entirely impossible for one-way clutches which should pivot or otherwise move already at low rotary speed under centrifugal force, by shifting position and lifting off either the inner or the outer race. Some clearance to the respective race is necessary.
In order to assemble sprags or friction-engaging elements of essentially circular shape, it is necessary to insert these elements before assembly into the cage or ring structure, together with the associated biassing springs. This requires multi-component cages, resulting in manufacturing and assembly costs which are higher than the unitary single-element cage or ring of the aforementioned U.S. Pat. No. 3,598,212, so that the cost advantage of the better, essentially circular friction elements is not effectively obtained in the overall clutch.